This invention relates to a novel method for preparing hexyn-3-ol-1. Particularly, the invention relates to an industrially economical method for preparing hexyn-3-ol-1.
Hexyn-3-ol-1, which is a valuable intermediate for the production of cis-hexen-3-ol-1, is conventionally prepared by either of the following reactions. One is a reaction between ethylene oxide and sodium salt of ethylacetylene which is derived from acetylene through the following reaction sequence as disclosed in the Journel of Chemical Society, 1950, page 877. ##STR1##
From the industrial point of view, this reaction has the disadvantages, such as, lengthy sequence of unit reactions, requirement of a pressure vessel owing to use of liquid ammonia (boiling point -33.degree. C.) as a solvent, and low yeild, say, 50% or less of the product.
Further, the other reaction is the following reaction as disclosed in Japanese Patent Disclosure No. 18406/1975. ##STR2##
According to this second reaction, 1,2-butadiene is a starting material which is converted in sequence into butynyl sodium, a butynyl magnesium halide and a halogenomagnesium salt of hexyn-3-ol-1, the last intermediate being hydrolyzed in the final reaction step to form hexyn-3-ol-1. However, it is disadvantaged in practice that the starting 1,2-butadiene is very expensive and the reaction for preparing the ethylacetylene magnesium halide requires tediously a long duration of stirring, say, 5 to 7 hours at a high temperature ranging from 50.degree. to 120.degree. C.